Johnny Sexton doesn't care about rankings and neither should Ireland

When Ireland were on top of the Rugby world last year I asked Johnny Sexton if being the number one ranked team in the world was a goal for this Irish team.

Ireland had just won the Grand Slam, they had won a summer series in Australia and they were aiming to become the first Irish team on home soil to defeat the world champion All Blacks.

Sexton was more concerned with New Zealand than he was with the rankings.

"Look, as players, we don’t worry too much about the rankings unless it’s coming up to that World Cup draw where you need to be in the top eight. I think the bigger motivating factor for us is to be in that first team to beat the All Blacks in Ireland.

"I was on the first Ireland team to beat the All Blacks in Chicago but to do it here in front of 50,000 people would make the atmosphere very special. I’m sure it would be a very special day in our careers."

If Ireland defeat England in Twickenham on Saturday it would at least, for a moment, rank Joe Schmidt's side as the number one team in world rugby and it's a feat that is not to be sneezed at.

Ireland were ranked eighth in the world when Schmidt first took charge back in 2013 and he now has the team in a position to take top spot with just under a month until the start of the Rugby World Cup.

It's a phenomenal achievement to complement Ireland's three Six Nations titles but the World Cup is about the last frontier left for this Irish team under Schmidt.

They've won the Six Nations titles. They've beaten the All Blacks, on home turf and abroad. They've won the Grand Slam. They've bested the southern hemisphere teams.

In the totality of Schmidt's reign the New Zealander has been an undeniable success but even if Ireland were to steal the number one spot from Wales this weekend it feels a little bit disingenuous.

Before last year's New Zealand test, All Blacks head coach Steve Hansen admitted that the winner of the game could lay legitimate claim to being the best side in the world.

Ireland defeated New Zealand 16-9 at Lansdowne Road and kept the Kiwis from crossing their line in a superb defensive display.

Ireland claimed second spot in the rankings but to many they were the number one team in the world and then the Six Nations came around a few months later.

Ireland were smashed up by England in the opening round, rallied over the next three games to claw back some wins against Scotland, Italy and France, before they were embarrassed by Wales in the final round. To borrow boxing terminology, they won the belt and lost it in their first defence.

The fallout from that Wales loss is still felt now, if not in the team, at least among supporters, and one warm-up win over Italy, with a largely experimental side, won't do much to restore public faith in this team but a win over a legitimate England side could be a good start in repairing trust.

It might be a warm-up match but it's a largely full-strength Irish side and a win over a near full strength England side may help heal some of the wounds from the Six Nations.

But even if Ireland do win, and even if they follow up that win with one or even two victories over Wales in their final warm-up games, it matters little unless they perform at the World Cup.

The only thing the 2011 warm-up games are remembered for is the end of David Wallace's career. The only thing the 2007 World Cup warm-up games are remembered for is the savage assault on Brian O'Driscoll.

The games are important for fitness and match sharpness, as well as the obvious purpose of providing a platform for fringe players to offer a final audition for a place in the squad, but they're rarely remembered for the wins or the losses.

The World Cup pool games are a different story. The collapse in 2007. The win over Australia at Eden Park in 2011. The win over France to avoid New Zealand in 2015.

Ireland have a relatively straightforward pool in Japan next month and should be able to get by Scotland, Italy and Japan but the knockout stages is where it gets tricky where Ireland will most likely have to play either New Zealand or South Africa; the reigning World Cup champions or the reigning Rugby Championship champions.

By that stage world rankings won't matter. The warm-up games won't matter. Rassie Erasmus and Steve Hansen won't care if Ireland are first, third or fifth in the world. They'll know what they're up against with Erasmus gaining intimate knowledge of the Irish team and structures through his work with Munster while Hansen can lean on last year's game as a pretty good indication of how Ireland will want to play.

The big question for Ireland is can they play how they want to play? We all know what Ireland looks like when they're winning but how can they change it up when they're losing?

Remember this is a team that had the most carries but the least amount of offloads in this year's Six Nations. They're a front-running team. They're not the type of team that can just throw caution to the wind and go for it when they fall behind. They play the percentages, they box kick and they suffocate teams and when they do it well they've proven that they can beat any team in world rugby when they're firing.

They have the talent, experience and coach to be the best team in the world but a number one ranking won't make us believe that. The only way we'll believe it is if we see Rory Best hoist the William Webb Ellis Cup.

This team has the potential to do that but the last few months has definitely damaged confidence levels. Twickenham is their first chance to mend some of the wounds but we won't see if they're fully healed until the knockout stages of the World Cup where they'll be really tested.

It's win or go home, but sure, we already knew that with this team. It's been like that for some time now.

Ulster and Ireland winger Jacob Stockdale joins Barry Murphy and Andrew Trimble for the latest House of Rugby episode. Jacob talks openly about some vile abuse he received online after Ireland's World Cup exit. He also speaks about rugby's return and his Lions ambitions.